1. Field of the Invention
The present invention relates to a light source for a display device.
2. Description of the Related Art
Display devices such as television receivers or computer monitors are classified as either a self-luminescence display capable of self-emitting or a light-receiving display requiring a separate light source. The self-emissive display device may be a light emitting diode (LED), an electroluminescence (EL), a vacuum fluorescent display (VFD), a field emission display (FED), or a plasma display panel (PDP). The light receiving display device may be a liquid crystal display (LCD) device.
Generally, the LCD includes a pair of panels having electrodes on their inner surfaces, and a dielectric anisotropy liquid crystal layer interposed between the panels. Varying voltage difference between field generating electrodes, e.g., a variation in the strength of an electric field generated by the electrodes, changes the transmittance of the light passing through the LCD to display a desired image.
In the LCD, the light may be natural light or an artificial light emitted from a light source that is separately employed in the LCD.
A backlight generally provides the artificial light to the LCD. The backlight uses light emitting diodes (LEDs) or fluorescent lamps such as cold cathode fluorescent lamps (CCFLs), external electrode fluorescent lamps (EEFLs), etc. as the light source.
The LED is eco-friendly because it does not use mercury (Hg) and it has a longer working lifetime than most other light sources. Further, the LED exhibits good color reproducibility.
However, the light emitted from the LED is typically condensed or focused to a very narrow area. For applying such an LED to a surface light source. Therefore, a technique for distributing the light from the LED to a wider region may be necessary to use the LED as a surface light source.